Electrical control system for ordnance fuzes



' H. P. ALLEN June 22, 1954 ELECTRICAL CONTROL SYSTEM FOR ORDNANCE FUZES Filed June 4, 1945 f- Defend/ar 45 0 2 fo d 3 @M yc/es Per Second/Y /00 WITNESSES: @afm ATTORNEY Patented June 22, 1954 ELECTRICAL `.CONTR L.;SXSTEM QRDNANCE EUZES r Harold P.. Allen,p..Mansleld, Ghio, assignolcby imesne assignments, to ethe fgUnitediiStaites. of Americaras `represented by the Secretary of the Navy -vrelatedzto a :-copendingiapplicationfof 1E.. J .g Nauf1 'tmanneandl L; W. Clarinv Serial.:` No. .597;574,. filed .aonfi'fheisamer datefas this application,A and.A .entitled ontrolgCircuit.

` In certain .othenfof.- its. .'aspects: this .invention .isn-elated---to a,;.copending application.offE.V J.

Naumann, Serial (No. 591571,- `filed on .the..saine :datexixas .thisff application, '.fentitled Electrically Operated Device-.and toria copending .application f- OffR.- `N .i1 Harmon and' EE; J .1, Vl\lauma;fir1,- Serial; N o. 597,573,- led-.ionv thesarnegdategfas .thisapplication, :and ,zentgitled1- Electrically '.Operated Devices, Jthe, foregoing; copendine; .applications-being .each .assigned :.tojthe ysamen assignee .asthis invention. Av'lrox-imityr iusestare applied toi various types. of hom'bs; shells, torpedoeaJv etc. andgiusually havea sinallx veryl compact :radio .transmitterv huilt. into the fuse, which isfgenerallyattached-to` the nose offtheirprojectile.- 'Theoperation of -..this `radio unit 'inf .I Ilosi-fxeases.l depends .upon the Doppler .effect hutgl-sometimesi.thefresulta is obtained. Joy photoelectric circuits or other meansfoelefctrical `.discharge or response; 'when'x the. fuse.: equipped projectileiapproaches its objective.

..vWith-.all-gsuh electrically operated.. proximity fuses, an-lelectrical; 'powerg supplyisrequiredsto energize thevariousg-components ofrthe electronic system.` -Inrrnost cases'Y these.l systems, in `addition 'tofvari ous 'low-voltage.. supply sourcesfrequire a highfvoltage.; plate supply for .the tubes,z..usually -of.y the order oi-..say,f-;150 Volts. ./Heretoiore small batteries; havefurnished: thefrequired electrical power. 'Ivhese batteries .have manyldisadvantages. Ingalmost-irall fus-esthe-spaceis limited-.and itis essential1;hat:.the powerfslipply; for; these fuses occupy v-,asflittlefspace as'. possible. x-E'or. thelmost paru-.suchsbatteries are bulky, andxmust. be'vmade up in f-'specialfcases to-e'onformzt-o .certain-'design requirements. The power produced with lrespect tothe size .of the .batteries must be; veryflarge: and asia consequence. supercharged `batteries;are needed. These have a. relatiyelysshortflifef.when stored.A .After ashortv storage period,y :their'power may ..drop to such ay low-.level as. tzr-render` them useless-.inav proximity fuse. Batteries are further objectionable in that theyarenot-dependable. .whenexposed to --lowteinperatures :Still further, with such fuse .power supplies vthere is .a constant danger that-.the .fuse inightfbeigexploded nadvertentlyfdueftoaa short circuitor; forfsome othenreason; resultnainsan electricalidiseharge 2 into. .the heater, zwhi'ch: ignites. .the squibpfortthe reason.y thati .the V.batteries throughout their .flife when .oncezconnected ain the .fuse .circuits -oleraan ever .present lsource of electrical energy.

AAs a consequence.; of'. the foregoing considerations,ggeneratorsnhavebeen v applied .as the .elec- I trical f energy-sources, in fusesystems.l Systems of this type form .thetsubjectmatter of.y ,the herein- '.before mentioned -f copending v.applications :Serial Nos.. 597,57l-anct-.597r,573. 1lrngeneral,1.these;sys

tems. .include ...au small. :alternator .which .has Aa permanent magnet -rotoridriren-hy.- arfluid oper- ;.ated device,such .essa propeller :or Aturloine which is g operated aby .the:.air1stream.-impingingconfgthe .propeller or. turbine `-bladf-zs. .when :theriuse .equi-ppedf. projectileis .proj ected. .intotthe ..atmose @here 11;Wi11 be apparent thatazshort timedelay is inherent;v before .the generator comes up .ito operatngzspeedi due tosuchreasons as .theiinertia of. the. .mechanicalgsysterna .themagneticridragfon .theI generator. :rotor and the. changing velocity ofgtheainstream,;tozmention a i-ew. y Duringfthis :p eriod :thezgenerator outputiand .frequency ofathe outputa.rising,v and,f.ins.the case of Doppler .Operated-devices, may pass.r through the rangeaof y.freque1lc-ies tQ-.swhichthe 4radior controlt-units .are responsive. '-,Unless adequate vprecautions :sare i'eiireri.v premature: detonation1-of lthe* projectile may-result.

. Inwutilizingagenerator as'. the .source-offenergy .in agyfuse, adequatestepsv` must: also be. takento insure az:close...control foithe-.voltagesavailable at the..generatoriwindings.v Notlonlycmust the voltage patterns bei similar, particularly over -the operating'. rangea of frequencies,`--but= alsofthe ratio of? the voltages zmust'nfbe Withinvery.. close limits of'. a;predetermined-ratio, for thefpurpose, among other ...purposes,.:of o'bviating: the I possibility of second-ary vfernissionxo wthe tubes linelectronic system partieularly.- iini fthe rcase :of Athe .oscillator transmitter. Theoceurrenceof secondary emissionmayresultlin n-iodulation` of the signal'being transmitted inthewfrequencyrange#of the` vlheat signal developed in the heterodyne,-circuits=with dgetonatiorr of -Lthef use resulting.

e .One obj ect..of `lthis invention is to provide -a fuse' ioreattachmentto a--1projectileiinV vwhich inadvertent: :detonatiorr thereof` `is obviated.

:.xAnother'.objectwof-this invention is to provide an .-r electrically operated' fuse Jpowered f-vby--=an alternator-f. or;` otherform -of fr alternating-current generator,.in whichthe maximum -outputof-the generator iseontrolled.

Yetyanother-:obj'ect .fofj .this invention is to :pro- Videfan ordnancafuseof the character mentioned 3 in which suitable tuning of the alternator output is provided to cause the voltage curve thereof to reach a maximum point at a prearranged time in iiight of the fuse equipped projectile or to maintain a minimum point for a given time.

A further object of this invention is to provide adequate control of the ratio of a pair of voltages available at an alternating current gen* erator.

Other objects and advantages will become apparent from a study of the following specification when considered in conjunction with the accompanying drawing, in which:

Figure 1 is a block diagram setting forth the principles of this invention.

Fig. 2 is a longitudinal cross section of a generator embodied in fuse systems of the class described.

Fig. 3 is a sectional view takenon the line III-lll of Fig. 2.

Fig.V 4 graphically illustrates the characteristics of two types of generator output regulation; and

Fig. 5 graphically illustrates the generator output regulation available with this invention.

A fuse of the type which depends for its operation upon the Doppler eiect is diagrammatically illustrated in Figure 1. Systems for the operation of such electronic fuses sometimes consist of a combination of transmitter and receiver in one circuit, the receiver being of the heterodyne type. The transmitting antenna elements Ia and Ib radiate energy to the target which, in turn, reflects the radiated energy back to the fuse. The reiiected energy wave or signal is received by the antenna elements Ia. and Ib and is mixed with the direct or transmitted signal as in a heterodyne receiver. The reflected signal frequency is dependent upon the velocity of the fuse with respect to the target, as well as the direct signal frequency. The Doppler frequency equations relate the direct signal frequency to the reflected signal frequency, if the velocity between the signal source and the observer, or in this case, the receiver, is considered equal to twice the relative velocity between the fuse and the target. This condition substantially obtains because the receiver is mounted with the transmitter in the fuse and thus has the same relative movement with respect to the target as the signal source or transmitter. Therefore, the reected signal, in most cases, differs in frequency from the direct signal. The reflected signal, upon being mixed with the direct signal, produces a beat frequency signal which increases in amplitude as the fuse approaches the target. The beat signal is amplified in the receiver and then passed to the trigger circuit where it is utilized, for example, to trigger a thyratron tube, which, when the beat signal amplitude is sufficient, becomes conducting and passes current through a heater in the detonator which ignites an associated squib forming part of a powder train in the detonator for igniting the main power charge of the fuse equipped projectile.

The contact members 44 and 45 in the circuits between the trigger circuit and the detonator include a stationary contact set which may, for example, be the set 45 and a movable set 44, the movable set being operated to engagement with the stationary set through a suitable mechanical connection with the propeller 2 indicated by the dotted line 46 which preferably includes a gear reduction unit 41 shown only in block form. In general, the purpose of such a contact arrangement is to introduce a safety feature to the fuse by preventing arming of the fuse until the projectile is in motion through the surrounding fluid medium and at a safe distance from the point of launching, at which time the propeller drive, after a predetermined number of propeller revolutions, closes the contact assembly.

The generator or alternator generally designated A has two windings in which are generated diiferent voltages. The main or high-voltage winding 3 primarily provides the plate volt age supply while the low-voltage winding 4 primarily supplies the filament circuits of the system. Figs. 2 and 3 illustrate a specific type of generator which has been employed in fuses. It includes a stator assembly 5 and a permanent magnet cylindrical rotor 6, spot magnetized for six alternate north and south magnetic poles. The stator assembly includes a sheet metal punching of magnetic material having a transverse section 'I and three finger-like members v8 extending axially therefrom in equal circumferentially spaced relation. A second punching of a similar character having a transverse section 9 and the finger-like members I0 is disposed with the finger-like members extending in the same axial direction as those of the first-mentioned punching and in equal circumferentially spaced interlocking relation therewith. The fingers I0 are shorter than the fingers 3 and when disposed so that they terminate in the plane defined by the extremities of the fingers 8 provide a spacing of the transverse sections 1 and 9 which are securely joined in this position by the combination core section and bearing housing II. The windings 3 and 4 are disposed about the core structure on a split tubular spacer I2 and a mounting plate I3 is secured against the transverse core section l. The rotor 6 for the generator is nonmagnetically secured to a shaft I4 journalled in bearings in the extremities of the core section II such that it rotates in the pole circle formed by the fingers 8 and I9, and a propeller or turbine, shown only fragmentarily at 2, is threadedly secured to the shaft extension opposite the rotor.

If north rotor poles are under the fingers 8 and south rotor poles are under the fingers i0, a magnetic flux will now from the rotor across the air gaps between the rotor and stator to the fingers 8, thence through the fingers 8 and integral transverse section 'I to the core section I I, through which the flux then passes to the transverse section 9 and integral fingers I0 where the path is completed across the rotor stator air gaps to the rotor south poles. As the rotor moves in rotation, the rotor poles reverse position under the fingers 3 and I0 and the flux through the stator reverses. This arrangement results in one alternation for each 30 of rotor movement. Therefore an alternating magnetic flux results in the magnetic circuit and the alternating magnetic iiux in the core section II induces voltages in the windings 3 and 4 linked therewith. Some control of generator output is obtained to give a flat characteristic above certain operating speeds by designing the generator to have a high leakage reactance or by operating the magnetic circuits at saturation above certain operating speeds. 1

Better regulation is obtained, however, by providing a regulating network in conjunction with the main generator winding 3. The action of this network in the main generator winding circuit is reiiected in the winding 4 by reason of 5. the..` closef coupling of- .the .-windingsl land-.aconsequentlyiregulationeof this: winding'alsozobtains;

Proper applicationlofthe regulation. circuitv of thisainvention irequires alcnowledge ofA `the-frequen'cyr rangeifover---which regulation is desired. Intordnance yoperati'onflit is possibleto knowxthe speedtofia projectileat any point :in its trajectory. WhenAv the speed of vthe-projectilefis known Ait is possible to calculate thefpropeller R.. sPM, andi, hence,find Athe 'alternator R.: PQM.' When the alternator R'.=P.l is known, Vthe fre quency vof the;alternatingl current supplied to the systemthrough the-rectifier `Fl rnay-be calculated. l3`v -suchv means it has been ifeund that fonaspecic application theialtern-ator- R; P. M; over its electrical'loperatingf rangera-ngeador example, from- 20,000 to 140,0 0-R'.l P. -M which for a six-pole1nacliineas illustrated produces an alternating voltagehaving a-frequency range oi roughly# from 1,000- -to- 3,000 cycles'l persecond. Thevupper speedflimit of the alternator, however, isfffnotea xed value and is known tofrunu as* h-igh ats-.100.000 1R. P. M.- Itis desgirablethat the-outpu'to-fthealternator beregulated over 4this entire range.

The specic generator illustrated undergoes a .reatancechange in; the. neighborhood-.of 9,500 ohmsto 14,000 vohmsduring the frequency change of 1,000 to 2,000 cycles per second. Hencegsthe generator may beiassumed to be .of neitherf. high. norlowmeactance... With. a. high reactance, generatorr arseries regulating capacitor vvilliproducev goodoutput regulation overa .certain frequencyrange. .As evidenced in. Fig. 4, however, lby ,theuppermost pair of curvesV designa-tederies legul ation a seriescapacitor, alone in the. Outnllt of, the ,mainwinding does not pro,- vide adequate voltage :contro-l overthe frequency range :of L.1,000 4to -2,000 cycles .perfsecond. There exists fa',` continuous psitive slope to the curves over the mentioned frequency range which is unsuited for the specic application of energizing the amplifier. Further the spread of the curves is too great. In this connection it is to be noted that the curves are plotted to the same scale but that the voltage of the main Winding is to be read 100 times the voltage indicated. The 100 to 1 ratio of voltages between the curves is thus not accurately maintained.

With shunt regulation as in the case of the two lower curves in Fig. 4 there results a reduction in voltage with a tendency to a flat response over the frequency range desired. The spread of the curves, however, is again too great although somewhat improved over the spread resulting from series regulation.

By providing a series connected resistor I8 and capacitor I9 in shunt relation with the main winding 3 and connecting a capacitor 20 in series in one side of the Winding output circuit it is possible to secure regulation as indicated graphically in Fig. 5. These circuit elements resistor I8, capacitor I9 and capacitor 20, are so selected in their reactance values in conjunction with the rectifier, lter and radio unit load that substantial circuit resonance occurs over the mentioned frequency range. In general the function of the series resonant circuit is offset in sucient degree by the characteristics of the parallel resonant circuit to produce the characteristic curves of Fig. which, it will be noted, are intermediate the two pairs of curves of Fig. 4 insofar-as magu nitude is concerned. There also results a much smaller spread in the curves which means the 6 1100..to. l1.' ratio of .voltages rdesirediis moreiclosly attained. l.

It iszvery :essential '.that. thespreadoi'voltages at'zth'e source. generator. are held Ato a..minimum'; Fuseszequipped with. such generators` operate over very..wide temperature ranges-n0t only 'in :the normal. application butalso depending upon 'the'. different climatic.l conditionsv under which ,they may be used. Such a conti-olasl provided:'tends to hold the: 1vol-tages 'close to desiredvaluesi over wide. excursions of temperature. The advantage-:sl of .this areevident.V 4It-permits greater latitudefin the `selection of circuitconstants `for the-radio units-ofthe4 fuse'and along with thi'sallow's greater variationor these constantsfin response toa temperature change without impairingl"the operation oi? the system. Y Y Y The -frequency range ofthe beat signal developedin the heterodyne circuitsv may "bef'of the-ordeivofxfrom 285* to 450Jcycles -perfsec di" The regulating circuitherein describedfby'pro# viding` anadequatecontrol .over the generator supply circuitslprovides a-sumciently smallvolt-f ageover'the generater frequency range corre-- spending toy the beat signal rangeithat'the-radiol unitsare inoperative As a result the radio" units' during this perioddo-not respondto the general tor r.signal .over vthe beat. signalfrequ'encyrange;T The-curves are not plotted'-below- 'cycl'esper secondibut it will be apparent-'from`-t'he slopef both-that the voltage Ydecreases at"lower *fr quencies and' will be somewhat-smaller i he range-or-the mentioned Doppler frequencies-of 285 .to 400 cycles pei-second. "'The tubes employed in the radio. system ofthe fuse are fairly :sensi ve as to energizing potentials-.anddo'notperas on'the, voltage v,availableJover the mentioned lotti frequencyl range.. 'I'he...volta'ge.v outputaover'. 'thefrequency range notedzis sufficiently,.flattoaprogy Videgood operation of ftheelectronicgunits.. ...In this connection it will be noted that in addition to the iattening of the voltage curves, the curves actually come closer together as the speed or frequency increases and slightly beyond 20,000 cycles per second meet, thus providing good voltage regulation both as to voltage magnitude and as to voltage ratio.

The foregoing disclosure and the showings made in the drawing are merely illustrative of the principles of this invention and are not to be interpreted in a limiting sense.

I claim as my invention:

1. Voltage generating apparatus including a regulating circuit having output terminals for use in a body operable through the atmosphere comprising, in combination, an alternating current generator having a pair of inductively related windings in which voltages are generated upon operation of said generator, air operated means for driving said generator, one of said windings being a high voltage Winding and the other of said windings being a low voltage winding, said regulating circuit comprising a capacitor and a resistor connected in series, said serially connected capacitor and resistor being shunted across one of said windings, and a second capacitor connected to said winding so as to be in series with any load connected to said output terminals, whereby when the frequency of the output voltages is less than a predetermined frequency the output voltages increase rapidly with an increase in frequency, and whereby when the frequency of the output voltages is greater than said predetermined frequency, the output voltages remain substantially constant.

'2. Voltage generating apparatus for use in a body operable through the atmosphere comprising, in combination, an alternating current generator having a pair of inductively related windings in which voltages are generated upon operation of said generator, air operated means for driving said generator, one of said windings being a high voltage winding and the other of said Y windings being a low voltage winding, a capacitor and a resistor connected in series, said seriallyT connected capacitor and resistor being shunted across said high voltage winding, rectifying means connected to said high voltage winding, a capacitor connected in series between said winding and said rectifying means, and a filter circuit connected with said rectifying means for filtering the rectied electrical output thereof.

3. An electrical control system for an ordnance fuse comprising, in combination, an electrical signal transmitting and receiving system adapted for transmitting a high frequency signal to an object, receiving the signal reected from the object, and thereafter mixing the transmitted and reected signals to produce a beat signal, an alternating current generator for energizing the electrical transmitting and receiving system and having a pair of inductively related windings, one winding being a high voltage winding and the other winding being a low voltage winding, a fluid operated device for driving said generator, disposed for operation upon motion of said fuze through a fluid medium, said fluid operated device operating over a wide speed range whereby the frequency of the output of said generator varies greatly, circuit means connecting said generator winding to said electrical signal transmitting and receiving system for energizing said system, said windings having voltages induced therein, the frequency of which passes through the range of frequencies of said beat signal, regulating circuit means connected between said high voltage winding and said electrical signal transmitting and receiving system for maintaining the output voltages of said generator at less than the minimum necessary for operation of the transmitting and receiving means when the frequency of the output voltages is within or below the frequency range of said beat signal, and for maintaining the output voltages substantially constant at the values required for operating said transmitting and receiving means when the frequency of the output voltages is above the range of frequencies of the beat signal, whereby premature operation of the fuze is prevented, and means responsive to said beat signal to operate the fuze.

4. An electrical control system for an ordnance fuze as defined in claim 3 in which said regulating circuit means comprises a resistance and a capacitance serially connected together, said serially connected resistance and capacitance shunting the high voltage winding of the generator, and a capacitance connected in series with the electrical signal transmitting and receiving system.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,104,257 Goldschmidt July 21, 1914 1,676,312 Alexanderson July 10, 1928 1,802,563 Kuhn Apr. 28, 1931 1,998,321 Kaar Apr. 16, 1935 I2,022,517 Patterson Nov. 26, 1935 2,186,847 Trogner Jan. 9, 1940 2,218,859 Schweitzer Oct. 22, 1940 2,259,982. Alexanderson Oct. 21, 1941 2,424,193 Rost et a1 July 15, 1947 2,468,120 Senn Apr. 26, 1949 

